A myocardial infarction (MI) occurs when a coronary artery becomes occluded and can no longer supply blood to the myocardial tissue. When a myocardial infarction occurs, the myocardial tissue that is no longer receiving adequate blood flow dies and is replaced with scar tissue. Within seconds of a myocardial infarction, the under-perfused myocardial cells no longer contract, leading to abnormal wall motion, high wall stresses within and surrounding the infarct, and depressed ventricular function. Infarct expansion and ventricular remodeling are caused by these high stresses at the junction between the infarcted tissue and the normal myocardium. These high stresses eventually kill or severely depress function in the still viable myocardial cells. This results in a wave of dysfunctional tissue spreading out from the original myocardial infarct region.
Known treatments for MI include invasive, open-chest surgical approaches to exclude, isolate, or remove the infarct region. Other potential surgical approaches, that also require the chest to be opened, include the application of heat to shrink the infarcted, scarred tissue, followed by the suturing of a patch onto the infarcted region. Other open-chest surgical treatments envision surrounding the heart, or a significant portion thereof, with a jacket to prevent further remodeling of the heart.